<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .hello{
            width: 100px;
            height: 100px;
            background: #ccc;
            
            /* display: none; */
            display: inline;
        }
        .world{
            display: inline-block;
            width: 200px;
            height: 200px;
            background: pink;
        }

        .container{
            width: 700px;
            height: 400px;
            background: #ccc;

            /*  弹性布局、弹性盒子 */
            display: flex;
            justify-content: space-evenly;
            align-items: center;
        }
        .container div{
            width: 100px;
            height: 100px;
        }
        .container .d1{
            background: red;
        }
        .container .d2{
            background: blue;
        }
        .container .d3{
            background: green;
        }
    </style>
</head>
<body>
    <div class="hello">嘿嘿</div>aaa

    <span class="world">哈哈</span>bbb
    <hr>

    <div class="container">
        <div class="d1">div1</div>
        <div class="d2">div2</div>
        <div class="d3">div3</div>
    </div>
</body>
</html>